Process for the alignment of railway tracks

ABSTRACT

The process forming the object of the invention aims at integrating into the performance of each automatic alignment cycle, an operation, likewise automatic, for compensating errors due to the track return phenomenon, without it being necessary to shift each corrected point of the track twice; this feature permits without difficulty, the use of the process for tampinglevelling-aligning machines, as well as for independent alignment machines.

United States Patent Sauterel et al. [451 May 23, 1972 PROCESS FOR THE ALIGNIVIENT OF [56] References Cited RAHJWAY TRACKS UNITED STATES PATENTS [72] Inventors: Gerard Sauterel, Pully; Andre Fomerod, 3,330,394 4/1963 Fomel'od /7 B G d b h of S i l d 3,486,461 12/1969 Plasser et al. 104/8 3,552,319 1/1971 Plasser et al. ...104/8 [73] Asslflnw Mime 1114mm Q1581", 3,547,039 12/1970 Plasser et al. ..104 s Switzerland 221 Filed: Mar. 20,1970 W' T Assistant Exammer-Rxchard A. Bertsch 21 Appl. No.: 29,333 Attomey-James M. Heilman and Heilman 8t Heilman [30] Foreign Application Priority Data [57] ABS CT The process forming the object of the invention aims at in- Mar. 24, i969 Switzerland ..4372/69 E g into the performance of each automatic alinmem cycle, an operation, likewise automatic, for compensating er- [52] 3 8 rors due to the track return phenomenon, without it being [5 1] 'f 3 l l1 necessary to shift each corrected point of the track twice; this [58] Field of Search ..33/60, 7 I146, 104/71,0'i1 feature permits without difficulty, the use of the process for tamping-levelling-aligning machines, as well as for independent alignment machines.

4 Claim, 4 Drawing figures PATENTEDMM23|912 3.664.265

sum 1 [IF 2 I) INVENTORS sRARo SAUTEREL BY ANDRE FORNEROD W22. MW

ATTORNEY.

PATENTEDMAY23 I972 3,664,265

SHEET 2 [1F 2 FIG. 3.

INVESTORS GERARD SAUTEREL BY ANDRfi FORNEROD ATTORNEY.

PROCESS FOR THE ALIGNMENT OF RAILWAY TRACKS Alignment is an operation carried out during the straightening of railway tracks, either using an independent alignment machine serving solely for this operation or using a more complex machine of the tamping-levelling-aligning type which simultaneously aligns, levels and tamps the track.

This alignment operation consists of eliminating, by a lateral displacement of the track using a force apparatus, the difference detected at successive points between the position of the track and the position desired at these points, said desired position being defined by a reference means.

This operation is generally automatic.

In use, it has been found that this process was insufficient to ensure a correct straightening of the track path. At the end of an alignment cycle when the track is released by the force apparatus at the desired position a partial return, of this towards the position which it occupied before straightening, occurs, particularly in the curves.

This track return phenomenon is due to the release of stresses previously existing or introduced into the track during its displacement by the force apparatus, a phenomenon which is made worse in the curves in the case of the simultaneous straightening of the track profile by a tamping-levelling-aligning machine by the lateral component of the natural weight of the raised portion of the track.

Errors due to this track return phenomenon are usually corrected by means of manual or automatic over-aligning.

With manual over-aligning, during each alignment the operator observes on an appropriate dial the position assumed by the track when released by the force apparatus. As a function of the error due to the return indicated on the dial, the operator again displaces the track by control of the force apparatus but not this time to bring it to the zero point of the reference means but beyond it in the opposite direction to the return until the track when released again returns to the desired position defined by the zero point. The slowness of such a process is obvious.

With automatic over-aligning the return is measured each I time after aligning the track to zero, this measurement is placed in a memory store, and a second alignment operation is performed at the same point with over-alignment, the amount of which is a function of both the memorized return and an over-alignment factor selected at the start of the work according to the track characteristics; all these operations are performed automatically.

This latter process offers a high degree of accuracy but involves a double alignment at each corrected point of the track.

The process forming the object of the invention aims at integrating into the performance of each automatic alignment cycle, an operation, likewise automatic, for compensating errors due to the track return phenomenon, without it being necessary to shift each corrected point of the track twice; this feature permits without difficulty, the use of the process for tamping-levelling-aligning machines, as well as for independent alignment machines.

This process is characterized by the fact that the alignment value at each point of the track to be corrected is composed of the algebraic sum of the value of the variation detected at this point relative to the theoretical alignment and a correction of which the value is a function of the track return measurement, performed at at least one of the previously straightened points.

In FIG. 1 attached, which illustrates this process, is shown a track V to be straightened according to a theoretical alignment XY. This track has the variations a,, a, a compared with the theoretical alignment at points 1, 2 N.

In a first alignment cycle point 1 of the track is aligned automatically according to d, at point l corresponding to its desired position on XY by cancelling out the detected variation a The track is then released by the force apparatus and under the action of the described return phenomenon returns to point l The absolute return value is r,.

In the following cycle this recorded value r is added to the detected variation a, between the point 2 and its desired position on XY, so that this point 2 of track is aligned by a value 4': at 2 so that:

d =a,+r When released the track returns at 2' and the new absolute return value r is recorded and introduced in the same way into the following cycle 3 wherein is obtained:

d3 a; +1: and so on, which for a random point N on the track can be written:

In this way the track is aligned according to an automatic control based on the continuous adjustment of the alignment asa function of successive absolute return values of the track. It should be noted that r,, can also be obtained by addition of the values b,, and c,, values measured relative to the desired alignment XY.

It is also possible without changing the final result of the process to use as the corrective element, instead of the measurement of the absolute return value of the track, that of the value of its relative return in relation to the desired alignment on XY, shown on the drawing by the values 0,, c c,,.

In fact, the first absolute return value r is equal to its relative return value 0 because the track was aligned on XY,

I thus 0, r

It can thus be written that at point 2:

The absolute return value at point 2 is:

r =c +c And at a random point N l:

This in fact says that the value of each absolute return of the track is equal to the algebraic sum of all the previous relative return values, including that of the relative return at this point.

The general formula based on the measurement of the absolute return values d =a,, r,,., becomes:

These two identical formulas give the value of successive alignments according to the process.

The process also permits, if necessary, the return measurement to be affected by a certain factor K, selected according to the characteristics of the portion of track to be straightened.

The general formula giving the value of each successive alignment then becomes:

FIGS. 2 and 3 attached, show means, given as an example, for performing this process.

FIG. 2 shows'schema'tically a reference means suitable for straightening the track path.

FIG. 3 (and 3 is the diagram of the hydraulic and electric circuits involved in the scope of the process according to the invention, said circuits being in the non-operative state.

In these two drawings the track is represented by the two lines of rails 13 and l3 FIG. 2 shows schematically a relative base reference of a known type using four potentiometers A,B,C,X, kept in contact with a line of rails 13 and connected with one another via an articulated transmission system designed in such a way as to permit the detection of any variation in the potentiometer X from the geometrical alignment defined by the three other potentiometers A,B,C.

The four transducers A, B C", X move with a railway machine which comprises, at least in proximity to the potentiometer X, a track alignment means represented in FIG. 3 by the alignment rollers 14.

The potentiometer X transmits its movements to the core 17 of a transducer 18, the casing of this sensor 18 being con nected mechanically to the three potentiometers A, B, C

This sensor 18 transforms the relative movements of its core 17 into electrical signals and in this case is a known type of electrical transducer having a differential transformer sensitive to the linear displacements of its core 17. The primary winding is fed by an alternating voltage of predetermined characteristics. Its two secondary windings l6 feed a closed circuit having two branches, of which each comprises an amplifier 19 and a primary winding of a transformer 20.

This closed circuit is designedin such a way that when the core 17 occupies a position which is symmetrical relative to the two secondary windings 16, the latter produce voltages of equal amplitude. Under the action of a movement of the core 17 caused by a displacement of the track level with potentiometer X, these two voltages differ in respect of their amplitude and phase, which permits their comparison by means of a measuring bridge. To this end the two voltages induced in the secondary windings of the transformers 20 are rectified by the demodulators 22 and diverted to two motorized potentiometers 23 and 24 by means of switches operated by electromagnetic relays. Switches 40,, and 40,, operated simultaneously by the relay 40 serve to invert, one relative to the other, the motorized potentiometers 23 and 24. Switches 41, and 41,, operated by the relay 41, fulfil the same function.

Each of the motorized potentiometers comprises a fixed central tapping (B for 23 and C for 24) and a mobile wiper; wiper A of potentiometer 23 being operated by the electrical servomotor 27 and wiper D of potentiometer 24 by motor 28.

A variation indicator 31 connected to the two center points B and C-of potentiometers 23 and 24 indicates the value of the error detected relative to the zero point of the reference means.

The voltage between points A and C or B and D defined hereinbefore, constitutes the signal used for the track alignment switch. The voltage between points A and D defined hereinbefore constitutes the signal used for determining the track position, this signal serving for re-establishing the equilibrium of the measuring bridge by shunting onto one of the motors 27 or 28, displacing the wipers A or D through the filter 29 and amplifier 30.

For alignment control, this signal is shunted on the control solenoid 33 of the servo-valve (33-34) through the filter 29 and the amplifier 30, as a function of the equilibration of the sources.

These shunts are provided by switches operated by electromagnetic relays, as will subsequently be described in the description of the operation of the means.

These relays, eight in number, each operate the switches carrying the same number plus a reference letter.

During the very short switching periods, so as to ensure that the servo-motors 27 and 28 cannot rotate, the resistance 10, capacitor 9 and diode 8 serve to attract by impulsion the relay 4 which earths the input of the amplifier 30, via switch 4,.

The alignment control signal is directed at the control solenoid 33 of servo-valve 34 which interconnects the pipes linking the two pressure chambers of a double-action jack 37 on the one hand to a pump 35 supplying the motor fluid and on the other to a tank for said fluid 36, in a conventional and known manner.

In the absence of a control signal, the servo-valve 34 occupies its median position, where the pressure chambers of the jack 37 are closed. The servo-valve is symmetrically and progressively controlled depending on the amplitude and sign of the electric signal.

Finally a double potentiometer 38-39 permits, by the double displacement of the wipers, the division of the voltage at the terminals of the wipers A and D relative to the median points B and C of the corresponding otentiometers.

The operating procedure using this means and according to the process of the invention takes place in 6 successive phases, comprising two consecutive track alignment cycles.

Phase I Automatic alignment of the track, positioning same from 1 1 (FIG. 1).

The operator operates the automatic alignment pedal 42 (FIG. 3'), which has the efi'ect of attracting simultaneously relays 1 and 6, then the delayed relay 2.

The error signal is taken between A the wiper of the motorized potentiometer 23 connected to the control solenoid 33 of servo-valve 34 via contacts 5,, 1 filter 29, amplifier 30, contact 1,. and the median fixed point C of motorized potentiometer 24, connected to earth via contacts 5,, and I The servo-valve 34 controls the lateral displacement of the track according to the size and direction of the error, up to the cancelling out of same.

Beforehand the wiper A is placed in front of the median point B of the motorized potentiometer 23.

Phase II Measurement of the transverse displacement of the track during its return (distance 1" l' or r,, FIG. 1).

When the operator releases the automatic alignment pedal 42 relay 1 is released, whilst delayed relay 2 remains attracted during the discharge time of its capacitor 7, which permits the relays 3 and 41 to attract via contacts 1,, 2,, and 5 relay 5 is attracted via 6,, and 1,, Whilst relay 6 remains attracted via 6,, and 1 (For the satisfactory operation of relays 5 and 6, a capacitor 6 is connected to the terminals of relay 6 in such a way that the latter remains attracted during the switching period of contacts 5,,, l, and 1,).

Relay 41 reverses the motorized potentiometer 24 for the return measurement time in order to reverse this measurement relative to zero in such a way that it is added to the error detected in the following alignment phase.

This return measurement signal is taken between the wiper A of motorized potentiometer 23 connected to the servomotor 28 via contacts 3,, and 1 filter 29, amplifier 30 and contacts 1,. and 41,, and the wiper D of potentiometer 24 con nected to earth via contacts 3,, and 1,,. Motor 28 displaces the wiper D of potentiometer 24 until the measuring bridge is again in equilibrium.

Phase III Advance of the machine from point 1 to point 2 (FIG. 1) Phase IV Automatic alignment of the track with correction (positioning ofthe track from 2 to 2 FIG. 1).

When the operator again operates the automatic alignment pedal 42, relays l, 2 and 5 are attracted and relay 6 is released because contact 1,, has been commutated.

The error signal is taken between B, the median point of the motorized potentiometer 23 connected to the solenoid of the servo valve 34 via contacts S and 1 filter 29, amplifier 30 and contact 1,. and the wiper D of motorized potentiometer 24 connected to earth via contacts 5,, and 1 It must be remembered that in phase 2 of the track return measurement, wiper D of potentiometer 24 was positioned by servomotor 28 so as to balance the measuring bridge after inverting the poten tiometer 24, resulting in the error measurement in this phase being composed of the algebraic sum of the error measurement relative to zero and of the return measurement performed in phase 2.

The servo-valve 34 controls the lateral displacement of the track according to the size and direction of this total error signal, until the cancellation of same by balancing the sources.

The position of the track at point 2 is thus rectified by a displacement at 2 of amplitude d a r,, according to the formula given in the description of the process (see FIG. 1). Phase V Measurement of the transverse displacement of the track during its return (distance 2 2 or r FIG. 1).

As the alignment control 42 is released, relays l and 5 are released, whilst delayed relay 2 remains attracted by its capacitor as well as 3 and 40 via switches l,,, 2,, and 5,, during the return measurement time.

As relay 40 is attracted it is this time the motorized potentiometer 23 which is reversed during the return measurement time in order to reverse this measurement relative to zero in such a way that it is added to the error detected during the fol lowing alignment phase.

This return measurement is taken between the wiper A of motorized potentiometer 23, this time connected to the servomotor 27- via contacts 3,, and 1 filter 29, amplifier 30, contacts 1 and 41,, and wiper D of motorized potentiometer 24 connected to earth via contacts 3 and 1,.

Motor 27 displaces the wiper A of potentiometer 23 until the measurement bridge has been brought into equilibrium. Phase VI Advance the machine from point 2 to point 3.

The phase cycle then recommences at phase 1, noting that this phase is an automatic alignment with correction as a function of the previous return measurement made in phase to be performed thus throughout the alignment process.

As has been stated in the description of the process, the means described also comprises a double potentiometer 3839, connected to the measurement circuit of the motorized potentiometers 23 and 24 which permits, by simultaneous displacements of their wipers, the variation of the amplitude of the track return measurement signal according to a particular coefficient selected as a function of the track characteristicsto be straightened.

What is claimed is:

l. A method for aligning railway tracks using a machine permitting the lateral displacement of the track to change the position thereof by canceling out the differences detected at successive points between their actual position and the desired position at these points while taking into account the track return phenomenon by a supplemental correction displacement beyond the desired position in order that after being released the track returns to said desired position, said method being characterized by the steps of:

displacing the track at each of these points at one time by a total correction value equal to the algebraic sum of two partial correction values, one of which is that of the variation measured at said point between the actual position and the desired position of the track and the other of which is a correction value equal to the measure of the actual return of the track effected at the preceding point; and

measuring and recording the actual track return value taken between the position where the track is released and the position-where it stops, for algebraically adding it as a partial correction value to the following point.

2. A method for aligning railway tracks using a machine permitting the lateral displacementof the track to change the position thereof by canceling out the differences detected at successive points between their actual position and the desired position at these points while taking into account the track return phenomenon by a supplemental correction displacement beyond the desired position in order that afier being released the track returns to said desired position, said method being characterized by the stepsof:

displacing the track at each of these points at one time by a total correction value equal to the algebraic sum of two partial correction values, one of which is that of the variation measured at said point between the actual position and the desired position of the track and the other of which is a correctionvalue equal to the algebraic sum of the measures of all the relative returns of the preceding points; and,

measuring and recording the value of the relative track return taken after the release thereof between the position where the track stops and the desired position thereof for algebraically adding it to the sum of the measures of all the relative returns which have been previously made in the same manner and obtaining the partial correction value to be added to the following point.

3. A method according to claim 1 in which, for each portion of the track to be aligned, the partial correction value is affected before being used by a certain coefiicient selected according to the characteristics of the portion of the track to be straightened.

4. A method according to claim 2 in which, for each portion of the track to be aligned, the partial correction valueis effected before being used by a certain coefiicient selected according to the characteristics of the portion of the track to be straightened.

k i i t 

1. A method for aligning railway tracks using a machine permitting the lateral displacement of the track to change the position thereof by canceling out the differences detected at successive points between their actual position and the desired position at these points while taking into account the track return phenomenon by a supplemental correction displacement beyond the desired position in order that after being released the track returns to said desired position, said method being characterized by the steps of: displacing the track at each of these points at one time by a total correction value equal to the algebraic sum of two partial correction values, one of which is that of the variation measured at said point between the actual position and the desired position of the track and the other of which is a correction value equal to the measure of the actual return of the track effected at the preceding point; and measuring and recording the actual track return valUe taken between the position where the track is released and the position where it stops, for algebraically adding it as a partial correction value to the following point.
 2. A method for aligning railway tracks using a machine permitting the lateral displacement of the track to change the position thereof by canceling out the differences detected at successive points between their actual position and the desired position at these points while taking into account the track return phenomenon by a supplemental correction displacement beyond the desired position in order that after being released the track returns to said desired position, said method being characterized by the steps of: displacing the track at each of these points at one time by a total correction value equal to the algebraic sum of two partial correction values, one of which is that of the variation measured at said point between the actual position and the desired position of the track and the other of which is a correction value equal to the algebraic sum of the measures of all the relative returns of the preceding points; and, measuring and recording the value of the relative track return taken after the release thereof between the position where the track stops and the desired position thereof for algebraically adding it to the sum of the measures of all the relative returns which have been previously made in the same manner and obtaining the partial correction value to be added to the following point.
 3. A method according to claim 1 in which, for each portion of the track to be aligned, the partial correction value is affected before being used by a certain coefficient selected according to the characteristics of the portion of the track to be straightened.
 4. A method according to claim 2 in which, for each portion of the track to be aligned, the partial correction value is effected before being used by a certain coefficient selected according to the characteristics of the portion of the track to be straightened. 